function [theta,dtheta,ddtheta]=cri_damping(t,theta_start,theta_end)
    wn=4.75;
    theta=theta_start+(theta_end-theta_start)*(1-exp(-wn*t)*(1+wn*t));
    dtheta=(theta_end-theta_start)*(exp(-wn*t)*wn^2*t);
    ddtheta=(theta_end-theta_start)*(exp(-wn*t)*wn^2*(1-wn*t));
end